Drive Train

Question 1

What is the purpose of the drivetrain?

Answer 1

Transmits rpm from the engine to the MR and TR

Question 2

Np RPM

Answer 2

32,183 RPM

Question 3

Torquemeter Gear RPM

Answer 3

10,528 RPM

Question 4

Power Output Shaft RPM

Answer 4

6,317 RPM

Question 5

MR RPM

Answer 5

413 RPM

Question 6

~TR RPM

Answer 6

2,497 RPM

Question 7

Transmission RPM Ratio

Answer 7

15.29:1 Reducing

Question 8

TR Gearbox Ratio

Answer 8

2.53:1 Reducing

Question 9

What does the drive train consist of?

Answer 9

Mast, transmission, main driveline (Kaflex), freewheeling unit, engine accessory gear box, TR driveshaft, oil cooler blower assembly, TR gear box

Question 10

Describe the mast

Answer 10

Hollow steel shaft
3 sets of splines: upper, swashplate, lower
2 threaded areas: upper and lower
Attached to transmission via locking plate and nut

Question 11

What is the purpose of the Main Drive Shaft and how does it fulfill that purpose.

Answer 11

The Kaflex provides a flexible connection between freewheeling unit and transmission
- allows for smooth torque transfer when the freewheeling unit and transmission are not aligned

Flexibility is provided by 3 rectangular plate sets in each coupling.

• each plate flexes as torque is carried axially through the straight parts of each plate
• provides for both angular misalignment and length changes as the transmission moves on its mounts

Question 12

Describe how the freewheeling unit works

Answer 12

Engine power - outer race - engaged sprags - inner race - main driveline (Kaflex)/TR driveline via flex coupling and splined adapter.

Question 13

Describe the Tail Rotor Drivetrain.

Answer 13

7 flexible segments

1. Steel - between engine accessory gearbox and aft firewall, has the AC compressor on it
2. Steel - after firewall, has the oil cooler blower on it

3-7. Aluminum shafts of equal length

• Supported by 6 hanger bearings that assist in maintaining driveshaft alignment
• Segments connected by 8 Thomas coupling disc packs, each with 9-12 steel plates (plates turned 90 to increase strength and flexibility

Question 14

Describe the TR gearbox

Answer 14

Magnesium housing gearbox attached to the tail boom by 4 studs and 2 alignment pins.
90 degree change using 2 spiral bevel gears
Speed reducing ratio 2.53:1
RPM ~2,497

Question 15

How many Chip detectors are on the drive train system and where are they?

Answer 15

6 total

1. In the TR Gearbox
2. In the Engine Accessory Gearbox
3. In the Transmission system: 1 in the freewheeling unit, 2 in the transmission case

Question 16

How is the Tailboom attached

Answer 16

4 bolts